Panigrahi Suraj Kumar, Mishra Ashok Kumar
Indian Institute of Technology, Madras, Chennai, 600036, India.
J Fluoresc. 2020 Sep;30(5):1085-1094. doi: 10.1007/s10895-020-02581-4. Epub 2020 Jul 6.
This article reports a time-resolved fluorescence data acquisition technique termed as "Total Emission Time Resolved Decay" (TETRD). TETRD is recorded by using zero-order diffraction of emission grating in TCSPC instrument. TETRD decay curve has entire wavelength dependent decay information buried in it. Cut-off filters are used to avoid scattering contamination. Two existing approaches are used for analysing the interconnected TETRD data. (i) First, global analysis: for discretely decaying multiple components, TETRD dataset is analyzed using global analysis. The normalized pre-exponentials (α) and relative amplitudes (f) recovered from global analysis reflect the individual component emission more faithfully and resembles with steady-state spectral data as well. (ii) Second, stretched exponential fitting (StrEF): for continuous lifetime distribution systems, StrEF (I(t) = I exp[-(t/τ)]) has been used to analyse TETRD data. The average lifetime (τ) of StrEF matches well with the average lifetime of multi-exponential fitting, the heterogeneity factor (h) of StrEF is an additional parameter, which informs about local heterogeneity in the system. It is shown that the lifetimes obtained with TETRD matches well with the lifetimes obtained using conventional time resolved emission spectra (TRES). TETRD holds advantage in rapid data acquisition and facilitates inclusion of another variable (like concentration, solvent composition, pH, excitation wavelength etc.) into experimental design. Further, with the use of an appropriate data analysis tool, the multi-component decay profiles can be resolved conveniently.
本文报道了一种时间分辨荧光数据采集技术，称为“全发射时间分辨衰减”（TETRD）。TETRD是通过在时间相关单光子计数（TCSPC）仪器中使用发射光栅的零级衍射来记录的。TETRD衰减曲线中蕴含着与整个波长相关的衰减信息。使用截止滤光片来避免散射污染。现有两种方法用于分析相互关联的TETRD数据。（i）首先，全局分析：对于离散衰减的多个组分，使用全局分析来分析TETRD数据集。从全局分析中恢复的归一化预指数（α）和相对振幅（f）能更忠实地反映各个组分的发射情况，并且也类似于稳态光谱数据。（ii）其次，拉伸指数拟合（StrEF）：对于连续寿命分布系统，已使用StrEF（I(t) = I exp[-(t/τ)]）来分析TETRD数据。StrEF的平均寿命（τ）与多指数拟合的平均寿命匹配良好，StrEF的异质性因子（h）是一个额外的参数，它能反映系统中的局部异质性。结果表明，用TETRD获得的寿命与使用传统时间分辨发射光谱（TRES）获得的寿命匹配良好。TETRD在快速数据采集方面具有优势，并有助于将另一个变量（如浓度、溶剂组成、pH值、激发波长等）纳入实验设计。此外，通过使用合适的数据分析工具，可以方便地解析多组分衰减曲线。
